Lead head nail



July 11, 1944. J. s. MAzE LEAD HEAD NAIL Filed May lOIv 1941 2 Sheets-Sheet 2 Patented July 11A, 1944 LEAD HEAD NAIL James S. Maze, Peru, Ill., assgnor to W. H. Maze Company, Peru, Ill., a corporation of Illinois Application May 10, 1941, Serial No. 392,840

2 Claims.

rial, and, in driving a nail through this-metal and :into the sheathing, considerable force is required in the hammer blowsdn order to pierce the metal and then properly seat the nail and seal the opening by means of the lead head ordinarily used.

. In the manufacture of lead head nails, particu- :larly lfor use in connection with corrugated metal, serious problems have arisen in that the soft lead head is deformed by the hammer blows before the nail has been completely driven in place. At-

-tem'pts have previously been made to provide means for holding the lead snugly in position around the nail head during driving. However,

none of these prior expedients have solved the H problem for the reason that the force of the hammer blows on such nails is not transferred directly to the rigid nail shank, but instead the lead coveringy provides a soft malleable cushion between the shank and the hammer and the material of this cushion flows under the hammer blows and causes the entire head to be distorted and loosened from the shank head and also from the shank itself below the head. This distortion occurs largely before the nail is completely driven in, and therefore the loosened and distorted lead head does not properly seal the opening in the sheet metal.

Furthermore, due to the distortion and loosening of the lead from the shank head and from the s'ank. itself, the lead head is easily puiled loose from the shank by the stresses due to expansion and contraction caused by sudden changes of temperature and by the intense heat of the corrugated material exposed to the sun. If the lead head can be made to retain its original shape and its. snug engagement with the shank head and the shank until the nail is completely driven into place, ythe lead head then conforms more accurately to the surface against Iwhich it is driven and more completely seals the opening around the nail shank and more effectively retains the seal. Modern roong nails for sheet metal roofing are now ordinarily provided with roll-threaded Shanks, the threaded portion of the shank being slightly larger than the normal diameter there- This requires either heavier hammer blows or more hammer blows in driving than is required with the old type of plain shank nails, so that the difdculty encountered in manufacturing lead head nails so that the lead head will not be loosened or distorted has been greatly increased.

The same problem has been encountered in manufacturing the old type of smooth shank lead head nails and has never before been effectively solved. However, the new type of Shanks makes the present invention of still greater importance. The rolled portion of the Shanks of these newer nails pierce a larger hole in the sheet than the normal diameter of the shank and therefore further increase the importance of an efiicient'lead seal.

f It is an object of the present invention to provide a lead head nail in which substantially all of the hammer blows applied in driving are transferred directlylto the shank of the nail and in which the lead head is not materially distorted nor loosened from any portion of the shank head or shank during driving.

A further object is the provision of a lead head nail of the character described in which the shank head and an adjacent portion of the shank is completely enclosed in lead in such a manner that the hammer blows in driving are transferred directly to the shank and in which the lead head retains substantially its original form during driving and is not materially loosened from any part of the nail proper.

Another object is to provide a lead head nail of the character described in which the shank head is completely enclosed With the usual thickness of lead and Without reducing the size of the entire nail head, but which at the same time enables the use ofa smaller amount of lead to accomplish the desired result.

It is also an object to provide a method of manufacturing lead head nails and eliminating the so-called 4piping eiect or sprue holes which have been formed in the upper portion of the head ywith previous methods of manufacture.

Further objects will be apparent from the specification and the appended claims.

In the drawings:

Fig. l is a side elevation of one of the nails having a low-pitch roll-threaded shank with the head of the nail shown in section.

Fig. 2 is a side elevation similar to Fig. l, but illustrates the application of the same type of lead head toga high-pitch roll-threaded shank.

Fig. 3 is a view similar to Figs. 1 and 2, but illustrates the lead head applied to the usual barbed shank nail.

Fig. 4 is an enlarged sectional View of the nail head before driving.

Fig. 5 is a detail sectional View of the same nail head shown in Fig. 4 after the nail has been partially driven into a support.

Fig. 6 is a detail sectional view of the ordinary nail head before driving. y

Fig. '7 illustrates the same nail head shown in Fig. 6 after being partially driven into a support to the same extent as shown in Fig. 5.

Fig. 8 is a sectional view of a slightly different embodiment of the invention in which the lm over the striking end is omitted.

mentioned patent.

`f Fig. yi) is a sectional view through an open die and punch and illustrates one method of manufacturing the lead head nails.

Fig. A is a sectional view similarto that shown in Fig. 8, but with the punch and die closed and the lead head completely formed on the nail shank. y

Fig. 11 .is a perspective view of one of the lead slugs from which the lead head is formed.

Referring to the drawings in detail, Fig. -1-illustrates a wire nail shank I having a sharpened point 2 vand a pilot portion 3 adjacent the point. The nail iis rolled to provide low-pitch threads 4 `formed vto present shoulders 5 facing the headiof .the nail, and these threads ordinarily are somewhat larger .than the normal diameter -of the :as illustrated. VThe shank I is similar to 'that mclosed .in the Maze Patent No. 2,226,006 and isprovidedwiththe usual head flange B. The shank yextends upwardly vbeyond this ilange to jform a-strikinghead 'I. It will be understood that the shank may be rolled in such a manner as to provide completely annular shoulders and grooves, if desired, as also shown in the previously `The striking head 1 projects upwardly from the `flange i a distance substantially equal to the thickness of the normal lead head above the ange and is preferably slightly tapered as shown so that the concentrated force of the hammer blows are directed to and distributed over the entire cross-sectional area o1' the shank. The

shank Aitself directly receives the full forceofthe Vhammer blow and there is no tendency to loosen the lead head.

A rlead head 8 or the like is pressed snugly around the flange i, the striking head 1, and a portion of the normal shank I. The lead forms la downwardly extending tapered portion 9 snugly engaging the shank and a downwardly extending peripheral flange I0, which latter, when it contacts the corrugated metal, is distorted suciently to conform to the surface of the crown of the corrugated material around the nail opening so as to prevent moisture entering therein as long vas the nail is held snugly in place.

The 'tapered portion 9 of the lead headenters into and closes the opening in the corrugated .metal and also provides an eiiicient seal. The top of the lead head of the nail is preferably convex as shown so that most of that portion oi the lead head around the projection 1 is slightly below 4the top of the projection. Also the lead forms a very thin film II over the top of the projection 1, or, if desired, the nlm may be omitted and the lead head be merely substantially flush Awith the top o1' the projection or striking head. The thickness of this lm isaexaggerated somewhat in the drawings, but in practice is only sufficiently thick to cover the top of the projection to enhance the appearance of the nail head as a whole. It serves no other -purpose and is sunlciently thin so that it has no material cushioning effect and does not materially interfere vwith the transmission of the force of l.the hammer blows directly to the shank itself.

It has been found in practice that it requires a less number of hammer blows to drive the nail of the'present invention than the usual lead head nail. In fact, when accurately calibrated test machines rare used for naildriving and twelve uniform blows of the machine are required to completely drive a lead head nail of the ordinary type not incorporating the applicants invention, it' requires only ten similar blows to drive the 75 same type of nail constructed in Vaccordance with this invention. Also, the lead head of the ordinary nail is loosened and distorted and its effectiveness as a seal is greatly reduced. With the nail of this invention, the lead head is not materially loosenedvnor distorted and a much more elective and permanent seal is provided.

With fewer blows required to drive and completely-set the nail, the corrugated metal is much less apt to be distorted, and, as the lead head is also set with fewer blows, it also is less distorted. The rapid puncturing of the corrugated metal by fewer lblows more effectively applied. makes a smaller hole in the corrugated metal, which smaller hole is more easily and eectively sealed. Furthermore, it has been found that, when the speed or force of the blows applied to the nail by-the test-machine is increased, the percentage ofdiflerence in the number of blows required to drive the respective nails is also materially increased and, at the same time, the lead head of the ordinary nail is distorted to a still greater extent while the head of the corresponding nail cut sections of nails driven of this invention remains undistorted.

`In view of the above noted tests, it is apparent that a workman driving the nails of this invention will expend much less energy and consume less time than when driving ordinary lead head nails.

The nails of the present invention provide many advantages in that they may be driven with fewer blows, the head remains tight and snugly secured to the shank during the entire process of driving, the normal contour oi the head is in no wise distorted, and the original design of the head is maintained until it is seated against the corrugated metal. Also the nail more easily pierces the metal sheet for the reason that the force of the blow is transmitted directly to the shank with no interposed cushioning eiect.

'I'he embodiment shown in Fig. 2 is substantially identical with that previously described except that the shank IB is provided with highpitch rolled threads I2 those disclosed in the Riedel et al. Patent No. 1,897,335. The type of head of the present invention is particularly important in connection with a high-pitch threaded shank as it permits free rotation Fig. 3 illustrates the same type of head secured to a wire nail having the usual barbed shank I". Fig. 5 illustrates the substantially undistorted nail of Fig. 4 after being partially driven into a support.

Fig. 'l illustrates the ordinary lead head nail of Fig. 6 after being partially driven into a support to the same extent as the nail shown in Fig. 5.

These views are accurately drawn from actual by the same machine. to the same extent, and with the same number of hammer blows applied to each. Large numbers of nails have been machine driven and these views accurately represent the results of these tests. After driving the nail of this invention as shown in Fig. 5, the lead head Il retains its original shape except for a slight flattening of the upper'.

convex surface as shown. This flattening is Very slight and is caused by the very thin lm II nowing outwardly and the pressure of the hammer on the lead closely adjacent the projection l. This small amount of lead and its outward flow is not sufllcient to Yforce the main body of the lead away from the nail proper. Also, due to the thinness of the illm, there is no material downward which may be similar tovv e of the nail under the hammer blows, without loosening or distorting the head.

or outward pressure on any of the lead around the shank I or flange 6, and therefore the lead head retains its original contour and its snug engagement with the shank and shank head.

As shown in Fig. '1, the ordinary lead head nail comprises merely a shank I22L having the usual integral head or flange I3 thereon, together with a cylindrical lead head I4 which may be of the same size and contour as that shown in Figs. 4 and 5. In the previously mentioned tests the nails were identical, with the exception of the projections 1 which are included in the structure shown in Figs. 4 and 5. As the hammer blows are applied to the nails shown in Figs. 6 and 7, the lead above the flange I3 provides a thick soft, malleable cushion which prevents the effectiveness of the blows from being directly transferred to the nail shank. The lead above the flange I1 is therefore iiattened out, as shown at I5, by forcing the lead outwardly and downwardly. This outward pressure loosens the lead around the shank of the nail, as shown at I6, and also provides an enlarged cavity I1 around and below the head of the shank. Therefore, as soon as the nail is even partially driven, the lead head is loose and freely rotatable and laterally movable upon the shank. Furthermore, the peripheral flange lll is distorted and rolled or turned inwardly due to the spreading4 of the upper and central portion of the head and, when it engages the corrugated metal, it tends to be forced inwardly instead of retaining its original cylindrica1 shape. The capacity of the ange or skirt to function as intended is destroyed and, therefore, the same effective seal cannot be formed as when the head is undistorted as shown in Fig. 5.

An important advantage of the present invention is also in conserving the amount of lead used. The nail industry is very competitive and any saving is of material importance. In the present invention, less lead may be used to form the nail head and the cheaper material of the shank substituted in the projection 1 with advantageous mechanical as well as financial results and at the same time retaining the same size and contour of head and the same amount of lead at the places where it is required for effectiveness.

Fig. 8 illustrates another embodiment in which the shank of the nail extends upwardly above the flange B* and the lead head 8* to form a striking In order to complete the formation of the lead head, a punch 2l is forced into the die so that the lead is snugly compressed into the form shown in Fig. l0 with only the very thin film II covering the top of the shank projection 1. The face of the punch 2| is preferably concave as shown so that the major portion of the lead, after the head is formed, is below the top of the shank projection 1. In manufacturing the embodiment shown in Fig. 8, the punch 2l will, of course, be provided with an axial opening to receive theend 1'A of the shank.

When threaded Shanks such as shown in Figs. l and 2 are used, in which the threaded portion is of slightly greater diameter than the normal diameter of the shank, the shank opening through the die and through the cup is also slightly larger than the normal diameter of the shank. However, this enlargement is slight and the pressure end 1. It will be understood that the striking end 1i may be ush with the upper surface of the lead or may extend above the lead as far as desired.V

Figs. 9 and l0 illustrate a method of manufacturing the lead head nails of this invention. This is accomplished by means of dies and punches. The present embodiment comprises a die I8 into which a lead disc or slug such, for instance, as shown in Fig. 11 is inserted and formed by means of a suitable punch, not shown, into a thickwalled lead cup I9 (Fig. 9). Simultaneously with the forming of the lead cup, the bottom wall is perforated at 20 and the depending tapered portion 9fi and the peripheral flange III are formed. The cup-forming punch is then withdrawn and a nail shank I is inserted in the die and through the opening 20 with the ange 5 resting snugly against the bottom of the cup. The cup is cylindrical and the side walls extend upwardly as shown and contain Just suillcient lead so that, when formed over the top of the flange 6, the lead will completely enclose the shank head in the manner illustrated in Fis. 10.,

on the lead causes it to snugly engage around the shank as shown.

In forming lead over the top of ordinary nail heads in which the projection 1 is not usedthe lead does not always close completely -at the center of the head and a piping effect or so-called sprue hole results such as indicated by dotted lines in Fig. 6. This objection is eliminated in the present invention and the lead always snugly engages all adjacent parts of the nail.

It is intended, of course, that the invention should not be limited to the specific embodiment or embodiments disclosed herein, since modifications may be made, and it is contemplated, therefore, by the appended claims to cover any such modifications as fall within the true spirit and scope of this invention.

Having thus described this invention, what is claimed and desired to be secured by Letters Patent is:

l. In a lead head nail of the character described, the combination with a pointed shank having a thin relatively small diameter substantially flat shank flange, and an axial striking pro- Jection extending materially above said shank flange. of a substantially cylindrical lead head completely enclosing said fiange and of a diameter to form a relatively thick wall around the periphery of said shank flange, said lead head having a thick marginal flange extending toward the point of said shank, the maior portion of said marginal flange being outside the diameter of said shank flange.

2. A nail for corrugated metal comprising a pointed shank and a shank head, said shank head comprising a thin flange having substantially flat upper and lower surfaces and a centrally disposed striking boss aligned with said shank, said boss being substantially the same diameter as said shank and havingl a substantially flat upper striking surface, a substantially cylindrical lead-like head completely surrounding said shank head and having a portion snugly embracing said shank and tapering toward the point thereof, the under surface of saidlead-like head being cupped to provide a comparatively thick dependent marginal edge, the major portion of the upper sur-- face of said lead-like head being sufficiently below the end of said boss that the normal hammer blows are concentrated on said boss and any flow caused by said normal hammer blows will be insufcient to cause displacement of the contactual relationship of said lead-like head/With said flange y 

